Discussion on: Properly validating e-mail addresses

^.+@.+\..+$ is the regex I use. It needs something before an @, something between that @ and a following ., and something after that ..

Does it accept some invalid email addresses? Probably. I ask users to verify their email address anyway; worst case scenario, they enter an invalid address and the email bounces. That one is on them.

Does it deny some valid email addresses? Maybe, but in my opinion if your email address is so weird it doesn't have an @ and a . in it, then you already know you're a signup error waiting to happen.

For a little while, I was hearing complaints from users who accidentally typed a space while entering their email address. So I added a validator to make sure the email address has no spaces. I know this denies even more valid email addresses, but my goal isn't to match the RFC perfectly, it's to allow the maximum number of users to sign up with the minimum number of problems. This prioritizes a large number of users who make mistakes over a tiny number of users who do not, which may not be fair but makes sense as a business decision.